1. Technical Field
The present disclosure relates to cathodes of lithium batteries and methods for fabricating the same.
2. Description of Related Art
Lithium batteries are used in various portable devices, such as notebook PCs, mobile phones, and digital cameras because of their small weight, high discharge voltage, long cyclic life, and high energy density compared with conventional lead storage batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries.
A cathode of a lithium ion battery should have such properties as high energy density; high open-circuit voltage versus metallic lithium electrode; high capacity retention; good performance in common electrolytes; high density; good stability during charge and discharge processes, and low cost. Among various active materials, transition metal oxides and mixed transition metal oxides have received much attention owing to their relatively high charge/discharge capacities in the lithium batteries. At present, the most widely used cathode active materials are spinel type lithium manganese oxide (e.g. LiMn2O4), olivine type lithium iron phosphate (e.g. LiFePO4), and layered type lithium cobalt oxide (e.g. LiCoO2).
However, the low conductivity of the active materials generally induces a relatively large resistance in the cathode. As such, the charge/discharge depth of the lithium ion battery is relatively low. To decrease the resistance of the cathode, a conducting additive is commonly mixed with the active material. The weight of the conducting additive can reach to about 10% of the total weight of the cathode. If the conducting additive is increased, the weight and the volume of the battery will increase.
What is needed, therefore, is a cathode of lithium ion battery and method for making the same that can overcome the above-described shortcomings.